Electromagnetic device.



G. C. CRAWFDRE. sucmommuenc DEVICE.

APPLICATION FILED NOV. 17. 1916.

1,248,461.. v Patented 1m. 4,1911

UN ITED STATES PATENT OFFICE. ousrnvns o. oiaawronn cr .EAs r onancn,Niaw nssrenon TO wEsTEitN ELECTRIC. COMPANY, INCOBPQBATED, NEW YORK, N.Y., A CORPORATION OF NEW YORK.

To all whom it may comm.-

Be it known that I, G-nsravos C. CRAW- noun, a subject of the King ofGreat Britain, residing at East Orange, in the county of Essex and Stateof New Jerse T have invent- 3 ed certain new and usefullmprovements inElectromagnetic Devices, of which the following is a full, clear,concise, and exact description. v p

This invention relates to electromagnetic devices and more particularly.to such devices commonly known as interrupters or pole changers. v I jThe object of this invention is the production of a devise of compactstructure and etficient operation which will also possess the featuresof simplicity, accessibility and ease of adjustment only to be foundpreviously in bulky and inefficient devices. This object has beenattained by the, use of a flat type magnetic structure hereinafter morespecifically to be described.

In the accompanying drawing isshown one embodiment of this invention,wherein Figure 1 a plan of an interrupter made up in accordance withthis invention; Fig. 2 is a side elevation with part of the base removedto show more clearly the core structure; and Fig. 3 is a cross sectionon the line 3 3 showing the contact points, contact springs and thevibrating armature. 7

Corresponding parts are designated by the same reference numeralsthroughout the drawing.

Referring now to the drawing, there are mounted on the wooden base 5,two fiat cores 6, 6 held together at one end by the magnetic yoke 7. Atthe opposite end they are secured to the base 5 by screws 8, indicatedby dotted lines. Energizing windings 9, 9 are provided for each core.The armature and armature mounting consists of an inverted L-shapedmember 10 adjustably secured to a yoke 7 by means of screws 11, 11, aribbon-like spring 12, a straight bar 13 and a cross bar 14. Theflexible spring 12, while holding the armature in operative relation tothe free end ,ofthe cores, allows the straight bar of the armature withits accompanying cross bar to vibrate in a direction transverse to theplane of the fiat cores. The separation between the cross bar of thearmature and the free ends of the cores depends upon the relativeposition of the yoke 7 and the inverted L-shaped member 10, which asherennnornonaennrrc DEVICE.

Specification of Letters Patent.

i atented Dec. 4,

Ap iicaaonineaitdveihter 17, 1916. Serial No. 131,874.

inbetore mentioned, is adjustable. As shown in Fig. 2, the screws 11, 11pass through slots in the yoke 7, thereby enabling the in verted Lshaped member-10 to be moved in a direction transverse to the plane ofthe hat cores and to be clamped in any desired position.

Under operating conditions, the circuit of the energizing or motormagnet windings 9, 9 is controlledby an interrupter contact 15 and aninterrupter spring 16. The contact 15 is secured to, but insulated fromthe L-shaped member 10 by means of screws 17 17 and suitable insulatingplates and bushings. Accommodated in a threaded hole at the treeend ofcontact 15 is an adjusting screw 18 carrying a contact point. Positioned I for engagement with this contact point and mounted on thearmature is the interrupter spring 16, which intermittently engages thecontact point of adjusting screw 18 as the armature vibrates. Inoperation, the vibration er the armature is caused by the intermittentenergization of the motor magnets 9, 9 whose circuit is intermittentlyopened by the disengagement of contact spring'16 and the contact pointoiadjusting screw 18.

Mounted on the free end of the straight bar, of the armature are thecontact springs 19 which have intermittent engagement with the contactpoints 20 when the armature is vibrating. The contact points 20 areadjustably positioned to engage the springs 19 by means of the adjustingscrews 21 mounted in threaded holes of the contact members .22. Contactmembers 22 are secured tothe base by means of screws 23, as indicated bydotted lines. The period of vibration of the armature is adjustablewithin lllll'ltQlOY means of the weights 24, 2 As shown in the drawing,the contact springs 19 are insulated from the armature 13 but this isnot essential to the invention.

It will beseen that the shape of the magnetic circuit not only makes thedevice highly eflicient, since practically a closed magnetic circuit isthereby obtained, but it also allows of a very compact structure, due tothe fact that the armature lies in a plane parallel to that of the core.This feature of compactness is especially important in the class ofservice for which this device is primarily adapted, namely, telephoneexchange systems. In the present state of developllt ment of thetelephone art, the amount of apparatus required to meet serviceconditions has so enormously increased that any reduction in the spacerequired for a given piece of apparatus, providing it does not decreaseits efficiency, accessibility or other desirable features, is of thegreatest importance. This invention, therefore, is of double importancesince it not only provides a device of smaller dimensions than anypreviously known but in doing so increases the efficiency of theapparatus by the shape of the magnetic structure employed.

The embodiment of the invention shown in the drawing has been found togive satisfactory service and represents the preferred embodiment of theinvention, but it is, of course, clear that many modifications of theexact structure are possible.

What is claimed is:

1. In an electromagnetic device, a magnetic structure comprising aplurality of flat cores, a magnetic yoke secured to the cores, anarmature flexibly secured to the yoke and in operative relation to thecores, a plurality of energizing windings for the cores, a contactmember secured to the yoke, a contact spring mounted on the armature,said contact spring adapted to be intermit tently disengaged from saidcontact member upon the vibration of the armature.

2. In an electromagnetic device, a plurality of eleetromagnets havingfiat cores, a magnetic yoke secured to one end of said cores to holdthem substantially parallel, a magnetic L-shaped member secured to saidyoke, an armature flexibly secured to said L-shaped member, a contactpoint in sub stantially fixed relation to said L-shaped member, and acontact spring carried by the armature and adapted to be intermittentlydisengaged from said contact point upon the vibration of the armature.

3. In an electromagnetic device, a plurality of flat magnetic cores, amagnetic yoke to secure the cores near one end, an armature, a magneticcrossbar secured to the armature adjacent to the free ends of the coresand adapted to move in a direction transverse to the plane of the cores,an ad justable means for flexibly securing the armature to the yokeeomprisin an L-shaped member having one limb adapted to bear against theyoke and adjustably secured thereto, and a ribbon-like spring secured tothe armature and to the other limb of the L-shaped member.

4. In an interrupter, a plurality of electromagnets having fiat cores, amagnetic yoke connecting said cores near one end, a magnetic L-shapedmember adjustably secured to the yoke, an armature, a ribbon-like springfor attaching said armature to said L-shaped member, a cross membersecured to said armature in operative relation to the unconnected endsof the cores, an adjustable contact member secured to, but insulatedfrom, the L-shaped member, and a contact spring carried on the armatureadapted to engage said contact member when the electromagnets aredeenergized.

5. In a pole changer, a plurality of electromagnets having substantiallyparallel flat cores, a magnetic yoke, said cores being connected nearone end by said yoke, an armature flexibly secured to the yoke andpositioned in operative relation to the unconnected ends of the coresand adapted to vibrate in a direction transverse to the plane of saidcores, a plurality of relatively fixed contact members, and a pluralityof contact springs secured to the armature for intermittently engagingsaid relatively fixed contact members upon the vibration of thearmature.

6. In a pole changer, an insulating base, a plurality of substantiallyparallel magnetic cores mounted thereon, a plurality of energizingwindings for the cores, an armature, means to flexibly secure thearmature to one end of the cores, an extension for the armature, acontact member secured to the base, and a contact spring mounted on thearmature extension adapted to intermittently engage said contact memberwhen the armature is vibrated.

7 In a pole changer, an insulating base, a plurality of electromagnetshaving flat cores secured to said base, a magnetic yoke secured to oneend of the cores, an armature flexibly mounted on the yoke and adaptedto vibrate in a direction transverse to the plane of the cores, anextension for the armature, a plurality of contact springs mounted onthe armature extension but insulated therefrom, a terminal membermounted on the base, said terminal member having a plurality of contactpoints, one of said contact springs being adapted to engage one of thecontact points when the armature is moved toward the cores, and anotherof said contact springs adapted to engage another of the contact pointswhen the armature is moved away from the cores.

In witness whereof, I hereunto subscribe my name this 16th day ofNovember A. D.,

GUSTAVUS C. CRAWFORD.

7 Copies of this potent may be obtained for five cents each, byaddressing the Commissioner of Patents,

Washington, D. G.

